Since my comment was to a "Guest" that got neg-bombed into a hidden comment, I'll copypasta it here in the main body:
It's actually been shown that it occurs when the lake beds flood, then freeze. The rocks then get pushed by the ice as it shifts around.
I learned this in 2nd grade. It's either the rain, winds and mud/wet sand, or it's the plates in the mantle. If so, earthquakes are causing rocks to move. YOU don't even have an answer.
It's actually been shown that it occurs when the lake beds flood, then freeze. The rocks then get pushed by the ice as it shifts around.
Another Spongebob reference.
You got taught wrong.
http://weknowmemes.com/2012/03/the-good-thing-about-science-is-that-its-true-whether-or-not-your-believe-in-it/